Process and device for full-cell treatment of timber or similar material



Sept 4, 1945' B. o. HGER ET AL Y 2,384,027

PROCESS AND DEVICE FOR FULL-CELL TREATMENT i oF TIMBER 0R SIMILARMATERIAL Filed March 12, 1945 "III II I IIIII 1| 'I I IIIIIIIDTI A.IIIII..4| I KN RSE me/rm mz' /afger SyBerilss 012 Kjellszom E( QM APatented Sept. 4, 1945 PROCESS AND DEVICE FOR FULL-CELL TREATMENT OFTIMBER R SIMILAR MA- TERIAL Bror Olof Hger and Stig BertilssonKjellstrm, assignors to Bolidens Gruvaktiebolag, Stockholm, Sweden, ajointstock company limited of Sweden Application March 12, 1943, SerialNo. 478,988 In Sweden February 8, 1942 (ci. zi-ss) Stockholm,

Claims.

The impregnation of timberland similar material is effected in practicemainly in accordance with the empty-cell or the full-cell process.' Theempty-cell process is adopted when the preservative is an oil, thefull-cell process when the pre- 1- ervative is dissolved or emulsifledin some cheap liquid such as water.

In principle, the empty-cell process proceeds in the following manner.The material to be treated is rst exposed in an impregnating cylinder toan initial air-pressure above the atmospheric pressure after which thecylinder is filled with the preservative oil, while the same pressure ismaintained. The pressure in the cylinder is then increased, whereby thepreservative oil is introduced into the material. After some time thecylinder is emptied of preservative oil and the material is subjected toa vacuum, whereby part of the preservative oil is expelled from thecell-cavities of the material by the internal air pressure whichprevails there. 'I'he consumption of the preservative oil is thusconsiderably reduced,as the cell-cavities will be only partially filledwith the preservative oil, whilst a uniform distribution of thepreservative oil in the material is nevertheless obtained. When treatingtimber with preservative oils it is for economic reasons necessary touse the empty-cell process.

By full-cell process the material to be treated is subjected in acylinder to a vacuum, after which the cylinder, while the vacuum ismaintained, is filled with a solution or emulsion of the preservative.The solution or emulsion is then Introduced into the material bypressure, so that the cell-cavities are filled with solution oremulsion. When treating with solutions or emulsions the amount ofpreservative absorbed by the material is controlled byregulating theconcentration of the solution or emulsion, so that the comparatively4complicated empty-cell treatment need not be resorted to.

The present invention relates to a process and device for effectingfull-cell treatment of timber and similar material. An impregnatingchamber or cylinder is charged with the material to be treated and isfilled with a liquid. All the liquid is thereupon expelled from thecylinder with a pump or pumps, the other inlets to the cylinder beingclosed, for creating a vacuum in the cylinder. By relling the cylinderwith liquid, letting out the air that has been sucked out from thetimber during the previous vacuum-stage, and pumping the liquid outagain the vacuum in the cylinder may be improved, if desired. When thevacuum has acted for some time, the

Sweden,

cylinder is lled with a preservative solution or emulsion, which is thenintroduced into the material by pressure.V When the material hasabsorbed the requisite amount of the solution or emulsion, the solutionor emulsion is again pumped out of the cylinder and air admitted. Thedripping from the material of the solution or emulsion after treatmentcan be reduced, however, by keeping out the air during the last-namedexpulsion state thus creating a vacuum. In this way small amounts of thesolution or emulsion `are sucked out from the outer layers of thematerial. The material, when completely impregnated, is removed from thecylinder and is allowed to dry.

As two illustrative embodiments of the invention two devices forfull-cell treatment are shown diagrammatically in Figures l and 2 of theaccompanying drawing. According to the rst of these figures, the deviceincludes an impregnating chamber A for the material to be treated, acontainer C Vfor the impregnating substance, and a pump D situated in aline, having a valve B, connecting chamber A and container C, inaddition to another line provided with valve E and located betweenchamber A and container C. The second gure includes the same elementsbut with the container C placed at a higher level rela-r tive to thechamber A, and with a valve F for the admission of air directly to thechamber A. 'I'he manner in which the respective devices are employed inpracticing the invention is described more fully hereinafter.

Referring now to Fig. 1, the device is used in the following manner: Theimpregnating chamber or cylinder A is charged with the material to betreated and is then closed, whereupon the valve B is opened and thecylinder A is lled with solution or emulsion from the container C bymeans of the pump D, while the valve E is open. When the cylinder A iscompletely filled with solution or emulsion the valve E is closed and,by the pump D, the solution or emulsion is pumped from the cylinder Aback to the conlrainer C, whereby a vacuum is produced in the cylinderA, and then the valve B is closed. When the vacuum has acted on thematerial for some time, the valve B is opened and the solution oremulsion is repumped'from the container C into ,the cylinder A,whereupon the pump (with pressure) forces the solution or emulsion intothe material. Any air that may have been formed in the cylinder A isdischarged through the valve E. When the material has absorbed therequisite quantity of solution or emulsion, the solution or Sis used inthe following manner. `nating chamber or cylinder A is charged with thematerial to be treated and is then closed,

emulsion is returned by the pump to the container C while the valve E isopen. 1n order to valve E closed during the last step of pumping thesolution or emulsion out of the cylinder A.

lThe valve B is closed and before the impregnated `material is removedfrom the cylinder A air is adlmitted to the cylinder A through the valveE.

Referring now toFig. 2, the device there shown The impregwhereupon thevalve E is opened so as to illl the `cylinder A with solution oremulsion from the container C. The valve E is closedV and valve B openedand by the pump D the solution or emullsion is pumped from the cylinderA back to the container C, whereby a vacuum is produced in `the cylinderA, and then the valve B is closed. `When the vacuum has acted on thematerial ior some time the valve E is opened, whereby the cylinder A islled with solution or emulsion from the container C, The valve E isclosed and the valve B is opened, whereupon the pump D (with pressure)forces the solution or emulsion into the material. When the material hasabsorbed the requisite quantity of solution or emulsion, the solution oremulsion is returned by the pump D to the container C while the valve Fis open. In

order to reduce the dripping of solution or emul- 1 sion from theimpregnated material after treatment, however, a vacuum can be formedanew in the cylinder A and upheld for some time by keeping the valve Eclosed during the last step of pumping the solution or emulsion out ofthe cylinder A. Before the impregnated-material is removed from thecylinder A air is admitted to the cylinder A through the valve F.

lower level than the rest of the plant. Owing to the simplicity of theapparatus, the management of an impregnation plant according to thepresent invention will be very easy. The initial and operating costswill moreover be low.

Having thus described our invention we declare that what we claim:

1.` A process for effecting full-cell treatment of timber or similarmaterial comprising charging an impregnating chamber with the materialto be treated, lling the chamber with liquid and then pumping out thesaid liquid, thereby creating a vacuum in the chamber, which after some1 time is iilled with a substance selected from the 4class consisting ofpreservative solutions and emulsions, the latter then being introducedinto the material by pressure.

2. A process for effecting full-cell treatment as claimed in claim l,wherein the liquid with which the chamber is first lled during thetreatment is a substance selected from the class consisting ofpreservative solutions and emulsions.

3. A process for effecting full-cell treatment of timber and similarmaterial as claimed in claim l, wherein the preservative substancecontains at least one arsenic compound.

4. A device for full-cell treatment of timber or 'similar material,comprising an impregnating chamber for holding the material to betreated, a container for a substance selected from the class consistingof preservative s'olutions and emulsions communicating with saidchamber, and means for creating a vacuum in said chamber prior tointroducing the preservative substance thereinto, said means includingpump means for filling said chamber with a liquid and for withdrawingsaid liquid to thereby create the vacuum in said chamber.

5. A device for full-cell treatment of timber or similar material,comprising an impregnating chamber for holding the material to betreated, a container for a substance selected from the class consistingof preservative solutions and emulsions, a conduit communicating withsaid chamber and with said container, and a single pump situated in thecommunicating conduit be-` tween the chamber and the container forcreating vacuum and pressure in the impregnating chamber and forconveying the preservative substance between the chamber and thecontainer.

BROR oLoF HAGER. sTIG BERTILSSON KJELLSTRM.

